Prior art systems for the generation of an image of an extended area operate in one of two ways. One method consists of synchronizing the movement of a photographic film across the face of the display oscilloscope with the movement of the camera detector head in front of the patient, the only record being the original photograph.
The other method is a rectilinear scanning system which consists of scanning radiation detection apparatus including a scintillation detector mounted for linear movement in opposite directions along a carriage. The carriage is itself mounted for linear movement in opposite directions orthogonal to the directions of movement of the scintillation detector, specific means being provided for moving the scintillation detector at a constant scanning speed and for reversing its direction at the end of each scan.
The major problem with the rectilinear scanning system using focusing collimators is that it suffers from inadequate depth of resolution and a low scanning speed. Furthermore, in the first method because the original photograph is the only record, there is no provision for data storage.